Build U Like are a building company specialising in hard landscaping. They lay patios, build walls, lay drives etc. for their customers. A customer will remain in the system even though they may not have any current or future building project(s) with the company. Each building project will consist of two parts: Material and Labour.

The material used by the company is supplied by a number of suppliers and each supplier can supply a number of different materials to the company.

The company keeps, on site, a certain quantity of all materials it uses and places an order with a supplier when the quantity in stock falls below a specified level. For simplicity, assume that there will always be an adequate quantity in stock for all projects and you need not take into account exceptional orders. In addition, assume that the material estimated as being used at the start of each project will be equal to the actual material used during the project.

Each project will be allocated one project supervisor and a number of staff who will be scheduled before the project starts. The allocation of the staff will depend on their area(s) and level of building expertise. A member of staff may be allocated to many different tasks on various projects. A member of staff may be scheduled for the same project more than once (scheduled for more than one task).

Task Allocation list for Project A:

Supervisor: ST7 Fred Bloggs

Staff member           Date               Duration        Task

ST1  L.Jones             10/11/09         14 hours        Laying Drive at front of property

ST2  L. Morgan         10/11/09         14 hours        Laying Drive at front of property

ST3  B. Smith            12/11/09           7 hours        Excavating area at rear of

Property

ST4  G. Samuel        12/11/09           7 hours        Excavating area at rear of

Property

ST1  L. Jones            12/11/09         21 hours        Laying Patio at rear of property

ST2  L. Morgan         12/11/09         21 hours        Laying Patio at rear of property

For simplicity, ignore the British weather and assume that the original schedule will always be adhered to. In addition, assume that staff will never need to be reassigned or rescheduled (no illnesses, unforeseen circumstances etc.).